In the nominative case, if we are counting something of size 2, 3, or 4 then the object being counted is in the genitive singular case, e.g., три треугольника. If we have an adjective involved, then it is genitive plural if the noun is masculine or neuter (e.g., три различных треугольника, три различных числа), but the situation with adjectives modifying feminine nouns that are being counted is more involved.
One reference I found said that in the nominative case after 2, 3, and 4 an adjective modifying a feminine noun is in the nominative plural (e.g., три различные функции). Another reference said that this rule is "normally" true if the noun has the same stress in genitive singular and nominative plural -- which I guess is what most feminine nouns are like -- and if the noun has different stress in genitive singular and nominative plural then the adjective is "normally" genitive plural (e.g., три различных стороны).
A) I'd like to know some counterexamples to these two stress tests for determining the case ending on adjectives modifying feminine nouns being counted by 2, 3, or 4. (If there weren't counterexamples then I'd think that reference would have explained the rules without the qualifying label of them being "normally" true.)
B) Is there a comprehensive rule for the case endings on adjectives modifying feminine nouns being counted by 2, 3, and 4 (with the numbers themselves being in the nominative case)?
I realize that anything applying to 2, 3, and 4 can be extended to other numbers ending in 2, 3, and 4 (except 12, 13, 14), but I keep the question restricted to 2, 3, and 4 for simplicity.